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SUMMARY:Cellulose Photonics: from nature to applications - Dr Silvia Vigno
 lini\, Department of Chemistry\, Cambridge
DTSTART:20170609T130000Z
DTEND:20170609T140000Z
UID:TALK72323@talks.cam.ac.uk
CONTACT:Hilde Hambro
DESCRIPTION:Nature’s most vivid colours rely on the ability to produce c
 omplex and hierarchical photonic structures with lattice constants on the 
 order of the wavelength of visible radiation [1].  A recurring strategy de
 sign that is found both in the animal and plant kingdoms for producing suc
 h effects is the helicoidal multilayers [2\,3]. In such structures\, a ser
 ies of individual nano-fibers (made of natural polymers as cellulose and c
 hitin) are arranged parallel to each other in stacked planes. When distanc
 e between such planes is comparable to the wavelength of light\, a strong 
 polarised\, colour selective response can be obtained [4]. These helicoida
 l multilayers are generally structured on the micro-scale and macroscopic 
 scale\, giving rise to complex hierarchical structures enriching their vis
 ual appearance.\n\nBiomimetic with cellulose-based architectures enables u
 s to fabricate novel photonic structures using low cost materials in ambie
 nt conditions [5-7]. Importantly\, it also allows us to understand the bio
 logical processes at work during the growth of these structures in plants.
  In this talk the route for the fabrication of complex bio-mimetic cellulo
 se-based photonic structures will be presented and the optical properties 
 of artificial structures will be analyzed and compared with the natural on
 es\n\n\n[1] Kinoshita\, S. et al. (2008). Physics of structural colors. Re
 p. Prog. Phys. 71(7)\, 076401. \n[2] Vignolini\, S. et al. (2012). Pointil
 list structural color in Pollia fruit PNAS 109\, 15712-15716.\n[3] Wilts\,
  B. D\, et al. (2014). Natural Helicoidal Structures: Morphology\, Self-as
 sembly and Optical Properties. Materials Today: Proceedings\, 1\, 177–18
 5. \n[4] de Vries\, H. (1951). Rotatory power and other optical properties
  of certain liquid crystals. Acta Cryst.\, 4(3)\, 219–226. \n[5] Dumanli
 \, A. G.\, et al. (2014). Controlled\, Bio-inspired Self-Assembly of Cellu
 lose-Based Chiral Reflectors. Adv. Opt Mat.\, 2(7)\, 646–650. \n[6] Park
 er R. et al. (2016). Hierarchical Self-Assembly of Cellulose Nanocrystals 
 in a Confined Geometry ACS Nano\, 2016\, 10 (9)\, 8443–8449\n[7] Kamita 
 G. et al. (2016). Biocompatible and Sustainable Optical Strain Sensors for
  Large-Area Applications Adv. Opt. Mat. DOI: 10.1002/adom.201600451.\n
LOCATION:Oatley Seminar Room\, Department of Engineering
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